Stem/leaf
4/2
5/
6/7
7/3,8
8/2,4,6
9/1,4
Y = 3x - 7 . . . . . (1)
6x - 2y = 12 . . . (2)
Putting (1) into (2) gives
6x - 2(3x - 7) = 12
6x - 6x + 14 = 12
14 = 12
Therefore, there is no solution.
Answer: Rewrite equations:
3x=y;x−2y=10
Step: Solve3x=yfor y:
3x=y
3x+−y=y+−y(Add -y to both sides)
3x−y=0
3x−y+−3x=0+−3x(Add -3x to both sides)
−y=−3x
−y
−1
=
−3x
−1
(Divide both sides by -1)
y=3x
Step: Substitute3xforyinx−2y=10:
x−2y=10
x−23x=10
−5x=10(Simplify both sides of the equation)
−5x
−5
=
10
−5
(Divide both sides by -5)
x=−2
Step: Substitute−2forxiny=3x:
y=3x
y=(3)(−2)
y=−6(Simplify both sides of the equation)
Step-by-step explanation:
The consumption rate of the car from previous part was 55 mpg (miles per gallon).We convert this to kilometers per liter.
1km = 06214 miles
1 gallon = 3.788 liters
hence, 55 mpg will be;
55× 1/0.6214×1/3.788 = 23.4 km / L
Thus, its mileage will be 23.4 km/L
For a distance of 1800 km the car will use; 1800/23.4 = 76.923 L
but, we know that the car gas tank holds 45 L
Hence, for a distance of 1800 km the car will use 76.923/ 45= 1.7094 tanks
That will be 1.7 tanks ( two significant figures)
